Blender file taking over an hour to load, is this normal?
10m vertices in a curve are a lot, especially since a bezier is subdivided even more between its control points. With a 2D curve, the filled shapes have to be calculated; another unoptimized step.

Some ideas.


Simplify the svg before exporting (in the exporter application).
Separate the svg in object mode. F3 > "Separate" [search]
Reduce the Preview Resolution of the curves.